1. Field of the Invention
The present invention relates to a deformable conductive elastomer configured so as to exhibit a high electric resistance value in a state of non-deformations such as non-pressurization and non-elongation, while exhibiting a well reduced electric resistance value at the time of deformations such as compression, elongation, torsion, and bending, and a manufacturing method thereof.
2. Description of the Prior Art
As this type of deformable conductive elastomer in the prior art, there is known, for example, one obtained by dispersing elastomer particles with a particle size of 10 through 300 xcexcm, conductive particles with a particle size of 10 through 40 xcexcm, and hollow elastic microspheres with a particle size of 10 through 150 xcexcm in a non-conductive elastomer, as disclosed in Japanese Patent Publication No. Hei 7-7607.
However, the prior-art deformable conductive elastomer as described above has the following problem in that the dispersibility of the conductive particles and the like is unsatisfactory, the variation characteristics of the electric resistance value with respect to repeated changes in pressure are unstable, and hence the reliability is not high.
Further, there are other problems as follows. Since wettability (adhesive strength) of the non-conductive elastomer which is a matrix, and the conductive particles are also unsatisfactory, a desired linearity cannot be imparted to the variation characteristics of the electric resistance value with respect to a change in pressure, as well as the mechanical characteristics such as the elongation percentage and tensile strength are also unsatisfactory.
The present invention has been achieved in view of the foregoing problems. It is therefore an object of the present invention to provide a deformable conductive elastomer excellent in reliability, linearity, and mechanical characteristics, and a manufacturing method thereof.
A deformable conductive elastomer according to a first aspect of the present invention for solving the foregoing problems is characterized in that elastomer particles with a particle size of 10 through 300 xcexcm and conductive particles with a particle size of 10 through 40 xcexcm are almost uniformly dispersed in a non-conductive elastomer.
The deformable conductive elastomer according to the second aspect of the invention is characterized in that ceramic particles with a particle size of 1000 nm or less are also almost uniformly dispersed in the non-conductive elastomer.
The deformable conductive elastomer according to the third aspect of the invention is characterized in that the non-conductive elastomer is a silicone rubber.
The deformable conductive elastomer according to the fourth aspect of the invention is characterized in that the silicone rubber is one obtained by crosslinking a mixture of a silicone varnish and an uncrosslinked silicone rubber, or a silicone adhesive containing the silicone varnish and the uncrosslinked silicone rubber as main components, and a liquid silicone rubber.
The deformable conductive elastomer according to the fifth aspect of the invention is characterized in that the elastomer particles are of a silicone rubber powder.
The deformable conductive elastomer according to the sixth aspect of the invention is characterized in that the conductive particles are spherical carbon particles.
A manufacturing method of a deformable conductive elastomer according to the seventh aspect of the invention, which is the manufacturing method of the deformable conductive elastomer described in any of the first through sixth aspects, is characterized by the steps of: adding at least the non-conductive elastomer uncrosslinked, the elastomer particles, and the conductive particles to a dispersion medium, vibrating, mixing, and drying the mixture to crosslink the uncrosslinked non-conductive elastomer.
The manufacturing method of the deformable conductive elastomer according to the eighth aspect of the invention is characterized in that the dispersion medium is a solvent in which the uncrosslinked non-conductive elastomer is dissolved.
The manufacturing method of the deformable conductive elastomer according to the ninth aspect of the invention is characterized in that the uncrosslinked non-conductive elastomer is a liquid rubber or an uncrosslinked rubber varnish.
A manufacturing method of a deformable conductive elastomer according to the tenth aspect of the invention, which is the manufacturing method of the deformable conductive elastomer described in the first, second, fifth, or sixth aspect of the invention, is characterized by the steps of: adding at least the non-conductive elastomer, the elastomer particles, and the conductive particles to a dispersion medium, vibrating, mixing, and drying the mixture.
The manufacturing method of the deformable conductive elastomer according to the eleventh aspect of the invention is characterized in that the dispersion medium is a solvent in which the non-conductive elastomer is dissolved.
The manufacturing method of the deformable conductive elastomer according to the twelfth aspect of the invention is characterized in that the non-conductive elastomer is a thermoplastic elastomer varnish.